Selective Hydrogen Removal Using Zeolite Catalyst
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Solution Overview
Problem
Existing processes for removing hydrogen from mixtures containing hydrogen and organic compounds are inefficient, often resulting in undesired reactions with oxygen that convert organic compounds into carbon dioxide or carbon monoxide, and do not effectively remove hydrogen.
Innovation Solution
A process involving a synthetic zeolite with a SiO2:Al2O3 molar ratio greater than 4:1 and a high degree of crystallinity, containing catalytic metals like Ru, Rh, or Pt, is used to selectively combust hydrogen with oxygen, producing water or steam while minimizing reaction with larger organic compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxygen gas is used to remove hydrogen from a mixture, then hydrogen removal efficiency is improved, but organic compounds are converted into undesired products like carbon dioxide or carbon monoxide
Solution Approach 1:
The patent applies local quality by using a zeolite support with specific pore size (0.3-0.5 nm) that creates a selective environment. The pore dimensions are tailored to allow only hydrogen and oxygen molecules to enter and react, while excluding larger organic compound molecules. This local structural property ensures that the catalytic metal sites are accessible only to the desired reactants, preventing unwanted oxidation of organic compounds while maintaining high hydrogen removal efficiency
Solution Approach 2:
The patent employs porous zeolite materials with controlled pore sizes (0.3-0.5 nm) as the catalyst support. These porous structures act as molecular sieves that selectively admit hydrogen and oxygen molecules based on their small size, while blocking larger organic compounds from reaching the catalytic metal sites. This porous architecture enables selective hydrogen combustion without side reactions, resolving the contradiction between removal efficiency and product purity
2Object-generated harmful factors
If sulfur dioxide or nitrous oxide is used to remove hydrogen, then organic compounds are protected from unwanted reactions, but hydrogen removal effectiveness is reduced
Solution Approach 1:
The patent applies parameter changes by switching from using sulfur dioxide or nitrous oxide to using oxygen gas as the oxidant. This parameter change is made possible by the introduction of the zeolite-supported catalytic metal system, which alters the reaction kinetics and selectivity. The catalytic metal on the zeolite support enables oxygen to selectively react with hydrogen at lower temperatures and with higher efficiency, while the zeolite pore structure prevents oxygen from attacking organic compounds. This parameter change resolves the contradiction by achieving both protection of organic compounds and improved hydrogen removal effectiveness
3Productivity
If conventional catalysts are used for hydrogen removal, then hydrogen can be removed from the mixture, but selectivity is poor and organic compounds are affected
Solution Approach 1:
The patent employs composite materials by combining catalytic metals (Pt, Pd, Rh, Ru, Ir) with zeolite supports having specific pore structures (0.3-0.5 nm). This composite catalyst system integrates the high catalytic activity of the metals with the selective molecular sieving properties of the zeolite. The zeolite component provides shape selectivity by allowing only small hydrogen and oxygen molecules to access the metal active sites, while blocking larger organic compounds. This composite structure achieves both high hydrogen removal capability and high selectivity, resolving the contradiction between productivity and manufacturing precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces hydrogen levels in the mixture, shifting the reaction quotient towards dehydrogenated organic compounds production without converting organic compounds into undesired products, thus improving the efficiency of hydrogen removal.
Implementation Method 1
contacting a mixture including hydrogen, oxygen, and one or more organic compounds with a synthetic zeolite to produce water or steam
Implementation Method 2
selectively combust hydrogen with oxygen, producing water or steam
Implementation Method 3
containing catalytic metals like Ru, Rh, or Pt, is used to selectively combust hydrogen with oxygen
Data Source
AI summary
Processes are provided for the removal of hydrogen from a mixture. The process can be performed by contacting a mixture comprising hydrogen, oxygen, and one or more organic compounds with a synthetic zeolite to produce water or steam. The synthetic zeolite can include Si and Al and has a SiO2:Al2O3 molar ratio of greater than 4:1, an 8-membered ring zeolite having a framework type of AEI, AFT, AFX, CHA, CDO, DDR, EDI, ERI, IHW, ITE, ITW, KFI, MER, MTF, MWF, LEV, LTA, PAU, PWN, RHO, SFW or UFI, a degree of crystallinity of at least 80% as measured by ASTM D535-197, and at least 0.01 wt % of at least one catalytic metal, based on a weight of the synthetic zeolite, where the at least one catalytic metal can include Ru, Rh, Pd, Ag, Os, Ir, Pt, Au, Mo, W, Re, Co, Ni, Zn, Cr, Mn, Ce, Ga, alloys thereof, or mixtures thereof. At least 95% of the catalytic metal can be disposed within a plurality of pores of the synthetic zeolite.